Even nature gets things wrong and so to weed out the sub standard it came up with survival of the fittest which was supposed to remove anything that failed to meet the standard.
Third obvious reason is that it's a machine and like all machines it will fail at some point.
And here's me sacrificing that valuable asset in the interests of
Someone in the US even now may be buying up such embedded blades and readying a clock production line. $299 plus taxes, P&P. WARNING: Do not disassemble and install in a table saw!
In any safety system failure is accepted but on two conditions, it fails safe and the failure is revealed. That is why a system that is designed to provide some safety function has to be tested end to end and initially a lot more frequently until you have enough history to support the stated SIL rating and that this system will perform on demand.
Your link is for 15+ year old stats.Hers's the most recent survey of US table saw injuries I can find:
https://www.cpsc.gov/s3fs-public/statsaws.pdf
The figures are rather damning.
Two main factors seem to be in play: a macho attitude that rejects safety devices as somehow a nanny thing not for real woodworkers; the unisaw design which has for decades eschewed riving knife, effective guards, a blade brake and many of the other safety features long built in to European table saws.
It does seem to be a behavioural/cultural issue. I can't find the report now but I recall reading one that looked at various kinds of "accidents" across different nations. On many fronts, with various potentially dangerous machinery, the USA was pro rata a highly dangerous place to work with such things compared to other first world nations and even some rather less developed nations. Their traffic "accident" rate was reported as poor compared to many other nations too.
Sawstop is, from one perspective, a highly necessary development for the US, since a lot of users refuse to adopt safe operating procedures recommended by the likes of HSE as "not convenient". Sawstop is the unavoidable nanny in their tablesaw that stops them self-harming.
I seem to recall that riving knives are now mandated by the US government on new table saws sold in the US (but not on the millions of old/extant ones). Another necessary nanny. Will some remove them on principle, to regain their freedom to enjoy a nice kickback from a plank?
If you can be bothered to trawl the US forums you'll find a few reports. The owners generally host them is a gush of praise for the device, which is understandable. Not just a finger saved but also a whacking great bill to mend it. Sometimes they describe how they came to put a finger on the blade but not always, as I recall. There are also reports of false positive firings or those when the detector can't distinguish between the finger and something with a similar resistance-profile to the detection circuit.
Once again you need to be corrected because your statement implies the saw never had them until recently. Factually incorrect that others read and pass along from which more incorrect assumptions are made.
It's an additional safety device. It doesn't replace push sticks and safe working. It is a last ditch attempt to save someones hand if they do something stupid or accidentally.
If I recall correctly they are designed to cut no more than 3mm into a hand/finger etc so should at worst leave a small cut. The alternative is to lose the finger/hand.
As I have said, failure is accepted and often expected as making any system with a 100% certainty of not failing is nigh on imposible and why in safety critical systems you get redundancy, ie in an aircraft you get at least two independant hydraulic systems so you have a backup. What you want is the sawstop to fail safe, this would mean it inhibits the operation of the saw and to be revealed so some form of warning like a lamp or audable beep. If this was a SIL4 rated safety system then you would still need to prove that the failure inhibits the saw but due to it's design proving it's primary function would be difficult unless the test was built into the sawstop. But one saw causing injury to one person does not warrant a high SIL rating.
Apologies for my bad syntax. I meant only that Sawstops do come with riving knives. And yes, they always have. But many still seem to use them without a guard, using only their hands to guide the workpiece - going by vids and magazine articles/pictures.
Forgiven.
